1. Technical Field
Exemplary embodiments described herein relate to a semiconductor device.
2. Description of the Related Art
Before, in order to secure the charge quantity induced by the channel of a MISFET (metal insulator semiconductor field effect transistor), a gate dielectric film has been decreased in thickness and a capacity has been enlarged.
As the result, a thin gate dielectric film (SiO2 film) is promoted, and its thickness can be below 1 nm.
However, when the gate electrode made of polycrystalline silicon is formed on the gate dielectric film made of SiO2, a depletion layer will arise in an interface with the gate dielectric film, and an Equivalent Oxide Thickness (EOT) of the gate dielectric film will increase.
When promoting a thin gate dielectric film, and to reach an EOT of a gate dielectric film being greatly below 1 nm, such EOT increase is a very big problem.
In order to address this problem, a method of using an oxide electrode is proposed in Japanese Patent Publication No. 2005-191354 (patent document 1).
In patent document 1, oxide conductors, such as Sr(Ti, Ru)O3, are used as an electrode.